Exam Time for IT. Ч.1. Практикум

Storage. Optical media — Compact Disks (CDs) and the similar-looking DVDs — are completely immune to magnetic fields. They can be run through airport X-ray machines without any problems. Flash memory is also immune to magnetic fields. Sometimes one can distinguish between «fixed media» (the hard drive) that is more or less permanently mounted inside the computer case, and «removable media» (just about every other kind of media) that is easy to pull from one computer and put into another computer.

Floppy Disk Drives. In the late 1960s IBM invented the 8-inch floppy disk. This was the first floppy disk design. Used in the 1970s and as a read-only disk it had storage-write restrictions to the people it was distributed to. However, later on a read-write format came about.

In today’s modem society it is rare to find a computer that uses the 8-inch floppy disk.

Hard Drive. A hard drive consists of one or more magnetic platters or disks and a read arm with two electromagnetic coils for each disk. Each hard disk is divided into many sectors, each containing a certain amount of data. As of now, it is the cheapest and most common way to store a lot of data in a small space.

CD-ROM Drive. Compact Disc Read Only Memory (CD-ROM) is a standard format for storing a variety of data. A CD-ROM holds about 700 MB of data. The media resembles a small, somewhat flexible plastic disc. Any scratch or abrasion on the data side of the disc can lead to it being unreadable.

CD-RWDrive. Compact disc Read/Write drives support the creation of CD-R and CDRW discs, and also function as CD-ROM drives. These drives use low-powered lasers to ‘burn’ data into the active layer of the disc. CD-R (Compact disc recordable) discs are ‘write once’ — once they have been written to, the data cannot be erased or changed. However, multisessions can be created and more data can be added.

CD-RW (Compact disc rewritable) discs can be rewritten or erased multiple times. This is a two-pass process so they typically take twice as long as CD-R discs to produce. CD-RW drives will typically have three speed ratings — one for reading discs, one for writing CD-R discs and another for writing CD-RW discs. Speed ratings vary from lx to 52x, where lx means that a CD is written/read in ‘real time’ — a 52 minute audio CD would take about 52 minutes to create at lx speed, and about 1 minute at 52x speed. The data can be written to the disc in a variety of formats to create an audio CD, a data CD, a video CD or a photo CD. The audio CDs should play on most standard audio CD equipment and the video and photo CDs will play on many consumer

DVD players. Many CD writers (also known as ‘burners’) are now combination drives which also function as DVD-ROM drives. Most DVD-RW drives also have CD-RW capabilities.

DVD-ROM Drive. Digital Video/Versatile Disk Read Only Memory (DVD-ROM) This optical drives work on a similar principle to the CD-ROM, with a laser being used to read data stored in pits on the surface of a reflective disk. DVDs are read using a shorter wavelength of light (a red laser, rather than an infra-red one). In addition to having a greater data-density,

DVDs may be double sided and may be «dual layer».

DVD-RW Drive. DVD’s hold about 4.7 gigabytes and dual-layer disks hold 8.4 gigabytes (dual layer equipment and disks are now more affordable).

BD-ROM Drive. BD-ROM Drive is a device used for reading data from a Blu-ray disc. Blu-ray is a high-density optical disc format for the storage of digital information, including high-definition video. The disc has the same dimensions as a standard DVD or CD. The name Blu-ray Disc is derived from the blue laser (violet coloured) used to read and write this type of disc. Because of its shorter wavelength (405 nm), substantially more data can be stored on a Bluray Disc than on the DVD format which uses a red (650 nm) laser. A dual layer Blu-ray Disc can store 50 GB, almost six times the capacity of a dual layer DVD. For both reading and writing data to and from a Blu-ray disc BD Writer is used.

Other Removable Media.

Flash Memory. Some common types of Flash memory cards are Compact Flash, Secure Digital (SD), and xD. There are other formats which have fallen into deprecation, such as

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Smartmedia and MultiMediaCard (MMC). Flash memory is faster than magnetic media and much more rugged. The only reason Flash hasn’t replaced hard drives is that Flash memory is much more expensive per gigabyte than hard drives.

USB Flash Drive. Memory sticks or Flash drives are solid-state NAND flash chips packaged to provide additional memory storage. These drives are quickly replacing floppy disks as a means of transferring data from one PC to another in the absence of a network. HD DVD is a high-density optical disc format and successor to the standard DVD. It was a discontinued competitor to the Blu-ray format.

Questions for self-check:

What parts does a typical personal computer consist of?

What are all instructions processed by?

Where is the data processed and turned into commands directed at the rest of the computer?

What is the advantage of having dual core?

What is hyper threading?

How is the case of most modern computers designed?

How is power supplied to a computer?

What is an exhaust fan that is responsible for?

How does the motherboard look like and function?

What is RAM needed for?

What kinds of cards are known to you?

What are the media of storing information?

Exercises:

1. Complete the sentences with the following expressions:

1. ... performs most of the calculations which enable a computer to function, sometimes referred to as the «brain» of the computer.

2. ... is used to lower the temperature of the computer; a fan is almost always attached to the CPU, and the computer case

will generally have several fans to maintain a constant airflow. Liquid cooling can also be used to cool a computer, though it focuses more on individual parts rather than the overall temperature inside the chassis.

3. ... is fast-access memory that is cleared when the computer is powered-down. RAM attaches directly to the motherboard,

and is used to store programs that are currently running.

4. ... is the most common type of removable media, inexpensive but has a short life-span. 5. ... a device used for reading data from a CD.

6. ... is a device used for both reading and writing data to and from a CD.

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7. ... is a popular type of removable media that is the same dimensions as a CD but stores up to 6 times as much information. It is the most common way of transferring digital video.

8. ... is a device used for rapid writing and reading of data from a special type of DVD.

9. ... is a high-density optical disc format for the storage of digital information, including high-defmition video.

10. ... is a high-density optical disc format and successor to the standard DVD. It was a discontinued competitor to the Blu-ray format.

11. ... is an outdated storage device consisting of a thin disk of a flexible magnetic storage medium.

12. ... is a flash memory data storage device integrated with a USB interface, typically small, lightweight, removable, and

rewritable.

13. ... is a device that reads and writes data on a magnetic tape, usually used for long term storage.

14. ... is for medium-term storage of data.

15. ... is a device similar to hard disk, but containing no moving parts.

2.Give Russian equivalents of the following words and expressions:

fan, case, connector, socket, coil, lane, slot, bunch, heat sink, mainboard, motherboard memory, chassis, designation, Hyper (-) Threading (HT), platter, multithreaded application, deprecation; rugged, in-between, immune, planar, backward-compatible, transparent, backup; mount, glow, supersede, plug, erase.

3.Find the word belonging to the given synonymic group among the words and word combinations from the previous exercise:

11.disapproval, disapprobation, blame;

4.Translate the words/expressions into English:

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разъем, гнездо; вытеснять; неровный, шероховатый; скопление, связка; устанавливать; монтировать, собирать; гиперпотоковость; совместимый назад; соединитель, разъем; обозначение, маркировка; вентилятор; подключать, вставлять в разъем; многопоточное приложение; стирать, удалять; корпус [ПК], системный блок, переходный, промежуточный; плоский; материнская плата; светиться, сверкать; дорожка (на магнитном носителе информации); катушка; обмотка; запасной, резервный, дублирующий; неуязвимый, невосприимчивый; дисковод для гибких дисков; прозрачный, просвечивающий; бежевый; теплоотвод; память материнской платы; корпус, блок, каркас; гнездо, розетка.

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Topic 6. Programming languages

Programming languages provide various ways of specifying programs for computers to run. Unlike natural languages, programming languages are designed to permit no ambiguity and to be concise. They are purely written languages and are often difficult to read aloud. They are generally either translated into machine language by a compiler or an assembler before being run, or translated directly at run time by an interpreter. Sometimes programs are executed by a hybrid method of the two techniques. There are thousands of different programming languages

— some intended to be general purpose, others useful only for highly specialized applications.

While it is possible to write computer programs as long lists of numbers (machine language) and this technique was used with many early computers, it is extremely tedious to do so in practice, especially for complicated programs. Instead, each basic instruction can be given a short name that is indicative of its function and easy to remember — mnemonic such as ADD,

SUB, MULT or JUMP. These mnemonics are collectively known as a computer’s assembly language. Converting programs written in assembly language into something the computer can actually understand (machine language) is usually done by a computer program called an assembler. Machine languages and the assembly languages that represent them (collectively termed low-level programming languages) tend to be unique to a particular type of computer. For instance, an ARM architecture computer (such as may be found in a PDA or a hand-held videogame) cannot understand the machine language of an Intel Pentium or the AMD Athlon 64 computer that might be in a PC.

Though considerably easier than in machine language, writing long programs in assembly language is often difficult and error prone. Therefore, most complicated programs are written in more abstract high-level programming languages that are able to express the needs of the computer programmer more conveniently (and thereby help reduce programmer error). High level languages are usually «compiled» into machine language (or sometimes into assembly language and then into machine language) using another computer program called a compiler. Since high level languages are more abstract than assembly language, it is possible to use different compilers to translate the same high level language program into the machine language of many different types of computer. This is part of the means by which software like video games may be made available for different computer architectures such as personal computers and various video game consoles.

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Every program ultimately has to be executed as a stream of bytes l h a t are instructions in your computer’s machine language. But human beings don’t deal with machine language very well; doing so has become a rare, black art even among hackers.

Almost all Unix code except a small amount of direct hardware interface support in the kernel itself is nowadays written in a high-level language. (The «high-level» in this term is a historical relic meant to distinguish these from «low-level» assembler languages, which are basically thin wrappers around machine code.)

There are several different kinds of high-level languages. In order to talk about these, you’ll find it useful to bear in mind that the source code of a program (the human-created, editable version) has to go through some kind of translation into machine code that the machine can actually run.

1. Compiled languages.

The most conventional kind of language is a compiled language. Compiled languages get translated into runnable files of binary machine code by a special program called (logically enough) a compiler. Once the binary has been generated, you can run it directly without looking at the source code again. (Most software is delivered as compiled binaries made from code you don’t see.)

Compiled languages tend to give excellent performance and have the most complete access to the OS, but also to be difficult to program in.

C, the language in which Unix itself is written, is by far the most important of these (with its variant C + +).

FORTRAN is another compiled language still used among engineers and scientists but years older and much more primitive. In the Unix world no other compiled languages are in mainstream use. Outside it, COBOL is very widely used for financial and business software.

There used to be many other compiler languages, but most of them have either gone extinct or are strictly research tools. If you are a new Unix developer using a compiled language, it is overwhelmingly likely to be С or C+ +.

2. Interpreted languages.

An interpreted language depends on an interpreter program that reads the source code and translates it on the fly into computations and system calls. The source has to be re-interpreted (and the interpreter present) each time the code is executed.

Interpreted languages tend to be slower than compiled languages, and often have limited access to the underlying operating system and hardware. On the other hand, they tend to be easier to program and more forgiving of coding errors than compiled languages.

Many Unix utilities, including the shell and BC and SED and AWK, are effectively small interpreted languages. BASICs are usually interpreted. So is Tel. Historically, the most important interpretive language has been LISP (a major improvement over most of its successors). Today, Unix shells and the Lisp that lives inside the Emacs editor are probably the most important pure interpreted languages.

3. Р-code languages.

Since 1990 a kind of hybrid language that uses both compilation and interpretation has become increasingly important. P-code languages are like compiled languages in that the source is translated to a compact binary form which is what you actually execute, but that form is not machine code. Instead it’s pseudocode (or p-code), which is usually a lot simpler but more powerful than a real machine limguage. When you run the program, you interpret the p-code.

P-code can run nearly as fast as a compiled binary (p-code interpreters can be made quite simple, small and speedy). But p-code languages can keep the flexibility and power of a good interpreter. Important p-code languages include Python, Perl, and Java.

Questions for self-check:

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What is the difference between natural and programming languages?

How can programming languages be translated into machine language?

How can machine language be defined?

What does a computer’s assembly language correspond to?

Are machine languages and the assembly languages that represent them identical for all types of computers? Why?

How can assembly languages be collectively termed?

What is the name of other types of programming languages? Give three basic characteristics to them.

1. Give English-Russian equivalents of the following words and expressions:

2.Choose the most suitable words from those given in brackets without consulting the text. Prove your choice. Translate the sentences into Russian:

1.Programming languages provide various ways of specifying programs for computers to (input, run).

2.Each basic instruction can be given a short name that is (indicative of, similar to) its function and easy to remember — mnemonic such as ADD, SUB, MULT or JUMP.

3.Some programming languages are (constrained, intended) to be general purpose, others useful only for highly specialized applications.

4.To write computer programs as long lists of numbers is extremely tedious in practice, especially for (embedded, complicated) programs.

5.Converting programs written in assembly language into something the computer can actually understand is usually done by a computer program called a (compiler, assembler).

6.Writing long programs in assembly language is often difficult and (benign, error prone).

7.Usage of different compilers to translate the same high level language program into the machine language of many different types of computer is part of the means by which software like video games may be made available for different computer architectures such as personal computers and various video game (consoles, screens).

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Topic 7. Telecommunication

Telecommunication is the assisted transmission of signals over a distance for the purpose of communication. In earlier times, this may have involved the use of smoke signals, drums, semaphore, flags, or heliograph. In modem times, telecommunication typically involves the use of electronic transmitters such as the telephone, television, radio or computer. Early inventors in the field of telecommunication include Antonio Meucci, Alexander Graham Bell, Guglielmo Marconi and John Logie Baird. Telecommunication is an important part of the world economy and the telecommunication industry’s revenue has been placed at just under 3 percent of the gross world product.

Etymology. The word ‘telecommunication’ was adapted from the French word ‘telecommunication’. It is a compound of the Greek prefix telemeaning ‘far off, and the Latin ‘communicare’, meaning ‘to share’. The French word was coined in 1904 by French engineer and novelist Edouard Estaunie.

Basic Elements. A telecommunication system consists of three basic elements: a transmitter that takes information and converts it to a signal; a transmission medium that carries the signal; and, a receiver that receives the signal and converts it back into usable information. For example, in a radio broadcast the broadcast tower is the transmitter, free space is the transmission medium and the radio is the receiver. Often telecommunication systems are twoway with a single device acting as both a transmitter and receiver or transceiver. For example, a mobile phone is a transceiver. Telecommunication over a phone line is called point-to-point communication because it is between one transmitter and one receiver. Telecommunication through radio broadcasts is called broadcast communication because it is between one powerful transmitter and numerous receivers.

Analogue or Digital. Signals can be either analogue or digital. In an analogue signal, the signal is varied continuously with respect to the information. In a digital signal, the information is encoded as a set of discrete values (for example ones and zeros). During transmission the information contained in analogue signals will be degraded by noise. Conversely, unless the noise exceeds a certain threshold, the information contained in digital signals will remain intact. This noise resistance represents a key advantage of digital signals over analogue signals.

Networks. A collection of transmitters, receivers or transceivers that communicate with each other is known as a network. Digital networks may consist of one or more routers that route information to the correct user. An analogue network may consist of one or more switches that establish a connection between two or more users. For both types of network, repeaters may be necessary to amplify or recreate the signal when it is being transmitted over long distances. This is to combat attenuation that can render the signal indistinguishable from noise.

Channels. A channel is a division in a transmission medium so that it can be used to send multiple streams of information. For example, a radio station may broadcast at 96.1 MHz while another radio station may broadcast at 94.5 MHz. In this case, the medium has been divided by frequency and each channel has received a separate frequency to broadcast on. Alternatively, one could allocate each channel a recurring segment of time over which to broadcast — this is known as time-division multiplexing and is sometimes used in digital communication.

Modulation. The shaping of a signal to convey information is known as modulation. Modulation can be used to represent a digital message as an analogue waveform. This is known as keying and several keying techniques exist (these include phase-shift keying, frequency-shift keying and amplitude-shift keying). Bluetooth, for example, uses phase-shift keying to exchange information between devices.

Modulation can also be used to transmit the information of analogue signals at higher frequencies. This is helpful because low frequency analogue signals cannot be effectively transmitted over free space. Hence the information from a low-frequency analogue signal must be superimposed on a higher-frequency signal (known as a carrier wave) before transmission.

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There are several different modulation schemes available to achieve this (two of the most basic being amplitude modulation and frequency modulation). An example of this process is a DJ’s voice being superimposed on a 96 MHz carrier wave using frequency modulation (the voice would then be received on a radio as the channel «96 FM»).

Society and Telecommunication. Telecommunication is an important part of modern society. In 2006, estimates placed the telecommunication industry’s revenue at $1.2 trillion or just under 3% of the gross world product (official exchange rate).

On the microeconomic scale, companies have used telecommunication to help build global empires. This is self-evident in the case of online retailer Amazon.com but, according to academic Edward Lenert, even the conventional retailer Wal-Mart has benefited from better telecommunication infrastructure compared to its competitors. In cities throughout the world, home owners use their telephones to organize many home services ranging from pizza deliveries to electricians. Even relatively poor communities have been noted to use telecommunication to their advantage. In Bangladesh’s Narshingdi district, isolated villagers use cell phones to speak directly to wholesalers and arrange a better price for their goods. In Cote d’Ivoire, coffee growers share mobile phones to follow hourly variations in coffee prices and sell at the best price.

On the macroeconomic scale, Lars-Hendrik Ruller and Leonard Waverman suggested a causal link between good telecommunication infrastructure and economic growth. Few dispute the existence of a correlation although some argue it is wrong to view the relationship as causal. Nevertheless, it is misleading to view the impact of telecommunication in purely economic terms as telecommunication has also had an significant impact on social interactions in many modern societies. For example, in 2000, market research group Ipsos MORI reported that 81 % of 15 to 24 year old messaging users in the United Kingdom had used SMS to coordinate social arrangements.

Due to the economic benefits of good telecommunication infrastructure, there is increasing worry about the digital divide. This is because the world’s population does not have equal access to telecommunication systems. A 2003 survey by the International Telecommunication Union (ITU) revealed that roughly one-third of countries have less than 1 mobile subscription for every 20 people and one-third of countries have less than 1 fixed line subscription for every 20 people. In terms of Internet access, roughly half of all countries have less than 1 in 20 people with Internet access. From this information, as well as educational data, the ITU was able to compile an index that measures the overall ability of citizens to access and use information and communication technologies. Using this measure, Sweden, Denmark and Iceland received the highest ranking while the African countries Niger, Burkina Faso and Mali received the lowest.

Questions for self-check:

What basic elements does a telecommunication system consist of?

How do signals differ?

How are networks structured and applied?

What does a channel represent?

How can modulation be defined and used?

What are the examples of telecommunication’s importance for modern society on the microeconomic and macroeconomic scales?

What does the increasing worry about the digital divide caused by?

Exercises:

1. Give Russian equivalents of the following words and expressions:

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semaphore; heliograph; arrangements; gross combat; transceiver; intact; reveal; discrete value; correlation; amplify; keying; attenuation; argue; digital; divide; render; exchange rate; convey; superimpose

2.Replace the marked words and expressions with synonyms from the previous exercise. Translate the sentences:

1.Often telecommunication systems are two-way with a single device acting as both a transmitter and communicator.

2.The shaping of a signal to transfer information is known as modulation.

3.A 2003 survey by the International Telecommunication Union (ITU) displayed that roughly one-third of countries have less than 1 mobile subscription for every 20 people and one-third of countries have less than 1 fixed line subscription for every 20 people. For both types of network, repeaters may be necessary to enhance or recreate the signal when it is being transmitted over long distances.

4.Unless the noise exceeds a certain threshold, the information contained in digital signals will remain undamaged.

5.Few dispute the existence of a link between good telecommunication infrastructure and economic growth although some argue it is wrong to view the relationship as causal.

6.This is to combat reduction that can make the signal indistinguishable from noise.

7.The information from a low-frequency analogue signal must be laid on a higher-frequency signal (known as a carrier wave) before transmission.

3. Translate the words/expressions into English:

показывать, обнаруживать; валовый; взаимосвязь, соотношение; манипуляция; приводить в какое-л. состояние, изменять состояние; приемопередатчик; неповрежденный, невредимый; расширять, увеличивать; валютный курс; утверждать, заявлять; цифровое неравенство; накладывать, наносить; меры, мероприятия; проводить (звуки), передавать; ослабление, затухание (сигнала); дискрет, дискрета; сражаться, бороться.

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